Device profiles provide color management systems with the information necessary to convert color data between native device color spaces and device independent color spaces. The International Color Consortium (ICC) profile specification (e.g., the current Specification ICC. 1:2003-09; File Format for Color Profiles (Version 4.1.0) [REVISION of ICC. 1:2001-12]) classifies color devices as: input devices, display devices and output devices. For each device class, a series of base algorithmic models are described in the ICC which perform the transformation between color spaces. These models provide a range of color quality and performance results that provide different trade-offs in memory footprint, performance and image quality.
The device profiles obtain their openness by using a well-defined reference color space and by being capable of being interpreted by any ICC operating system or application that is compliant with the specification. In combination with profiles for other devices color transformations may be determined that enable colors captured on one device to be reproduced satisfactorily on many others.
The ICC Profile Format supports a variety of device-dependent and device-independent color spaces divided into three basic families: 1) CIEXYZ based, 2) RGB based, and 3) CMY based (including CMYK). A subset of the CIEXYZ based spaces are also defined as connection spaces. Vendors of device color profiles use a wide variety of algorithms for constructing output device profiles. There are variations in the underlying algorithms used to derive the calibration and characterization. More importantly, the gamut-mapping algorithms used in the various rendering intents can be vastly different. This can lead to two problems: i) a user may not be satisfied with the color reproduction obtained with a given vendor's profile; and ii) there is a greater chance for inconsistencies in color reproduction even with a single device or family of devices. In addition, if the user changes the digital front-end (DFE) configuration, jobs that were printed satisfactorily earlier either require significant re-work or a restoration of the configuration. For example, a user of one DFE may adopt a different DFE for a new purchase, but may wish to preserve the “look and feel” of the original DFE for jobs previously rendered on that DFE.
Disclosed herein is a system and method for adjusting a device profile according to a user-specified aim. The desired aim can be specified in one of several ways: i) “Custom parametrics aim”, which uses parameters and profiling algorithms as set by the entity; ii) an industry standard aim, e.g. Specification for Web Offset Publications (SWOP) or sRGB; iii) an aim profile; or iv) a graphical user interface to interactively adjust one or more color images, whereby the resulting adjustments collectively define the desired aim. In one embodiment, the user uploads the device profile to a website, and specifies a desired aim. A web-based profile adjustment service derives a new profile that meets the desired aim, and makes it available to the user for downloading at the same site. The profile adjustment service may additionally communicate with a profile discovery service to assist the user in specifying the aim.
The system and method advantageously enable the user to incorporate a desired aim or “look-and-feel” into an existing 3rd party profile without the need for additional measurements, calibration or characterization. They can be used to adjust multiple profiles associated with different vendors and different devices towards a common aim. Finally the system and method can be used for device emulation by specifying, as the aim, a profile for the device being emulated. The invention is easily enforced via the user interface to the service, as well as the resulting adjusted profiles, which are an outcome of a unique combination of original profile and user-specified aim.
One aspect of the system and method described herein is based on an observation of problems with conventional rendering systems, and the difficulty in modifying such system to achieve a preferred output consistency. This aspect is based on the discovery of a technique that alleviates these problems by providing a user with the ability to alter profiles and/or emulate the operation of alternative output devices through profile adjustment. This technique can be implemented, for example, using automated, on-line or local, adjustment of profiles in response to user-specified aims for a color reproduction device. The techniques described herein are advantageous because they provide a range of alternatives, each of which is useful in appropriate situations. As a result of the system and method described in detail below, a user is provided a way in which to adjust a device profile to meet the user's aim.
The following written description includes a preferred embodiment, however, it will be understood that there is no intent to limit the scope of the invention to the embodiment described. On the contrary, the intent is to cover all alternatives, modifications, and equivalents as may be included within the spirit and scope of the description and the appended claims.